Abstract: In this work,the rhizosphere soil samples at three stages of kiwifruit development were collected from the kiwifruit planting base in Yongshun County,West Hunan.The bacterial community composition and population abundance in the canker and healthy samples were analyzed by metagenomic sequencing.The results showed that there were some differences in the bacterial community composition and population abundance in three periods of rhizosphere soil samples of the healthy and diseased kiwifruit,but the dominant bacteria mainly included AcidobacteriaGp,Gemmatimonas and Gaiella.The population abundance of Pseudomonas increased and then decreased with three stages of kiwifruit development,coinciding with the process of kiwifruit canker disease,which indicates that the rhizosphere soil bacterial community is one of the infectious sources for the kiwifruit canker occurrence.In addition,it was found the abundance of flavobacteriaceae and comamonadaceae was higher in the canker samples than in the healthy samples,presumably positively correlated with the occurrence of kiwifruit canker disease.The abundances of Rhodospirillaceae,Thermomonosporaceae,Bacillus and Streptomyces were higher in the healthy samples than in the diseased samples,presumably playing an antagonistic role in the occurrence of kiwifruit canker disease.

Key words: kiwifruit canker disease, rhizosphere soil, metagenomic sequencing, bacterial community composition